BRIEF SUMMARY Trachoma, caused by ocular chlamydia infection, is the most common infectious cause of blindness worldwide. The World Health Organization recommends the SAFE strategy for trachoma elimination: Surgery for inturned eyelashes, mass Antibiotic distributions to reduce the community burden of chlamydial infection, and Facial cleanliness and Environmental improvements to reduce transmission of ocular chlamydia. However, little evidence from randomized trials exists to support the ?F? and ?E? components of the SAFE strategy. The present study, called WUHA II, is a continuation of the WUHA I trial. WUHA I is an ongoing cluster- randomized trial in rural Ethiopia designed to determine the effectiveness of water, sanitation, and hygiene (WASH) for trachoma. 40 communities were randomized in a 1:1 ratio either to a comprehensive WASH package or to no intervention. The primary outcome is ocular chlamydia, monitored annually for 3 years. In WUHA II we will treat all 40 WUHA communities with a single mass azithromycin distribution after the month 36 visit, and then continue the WASH intervention only in the 20 communities originally randomized to the WASH arm. We perform annual monitoring visits at months 48, 60, 72, and 84 for the primary outcome of ocular chlamydia among 0-5 year old children. Secondary outcomes include clinically active trachoma from conjunctival photography, chlamydial load from quantitative PCR, serologic tests for chlamydia, and nasopharyngeal macrolide resistance, each assessed in children aged 0-5 years. A second aim of WUHA II is to perform a diagnostic test accuracy study of the tests already being conducted as well as several novel tests for trachoma surveillance. The novel tests include inexpensive, point-of-care nucleic acid amplification tests performed on conjunctival swabs, a lateral flow assay for chlamydia seropositivity tested on dried blood spots, and an automated algorithm to detect clinical signs of trachoma from conjunctival photographs. The primary objective of the second aim is to test the sensitivity and specificity of each of these trachoma surveillance tests. By comparing the combined azithromycin-WASH communities to communities receiving mass azithromycin alone, we investigate the benefit of combining the ?A?, ?F?, and ?E? components of the SAFE strategy as opposed to focusing on antibiotics alone. This is an important question given the expense of WASH interventions and the limited resources of trachoma programs. WUHA II also provides information on novel trachoma surveillance tests, which will become more crucial as the world nears elimination.